Selwyn ratepayers will be asked to pay a one-off $60 transport rate to help keep the fast-growing district's roads in good order.

The extra payment lifts the average Selwyn rates rise to 7.8 per cent, according to the draft annual plan which was yesterday adopted and released for public feedback.

Without the new transport rate, the average increase would have been 4.9 per cent.

Chief executive David Ward said the council faced a challenge in paying for road maintenance and new roads.

That work had been partly subsidised by the New Zealand Transport Agency but that contribution was now below what the council believed it needed.

Ward said an extra $1 million would be raised through the rate.

"This means that if we wish to continue to maintain our roads in a good state of repair, ratepayers will need to spend more. . .

"Selwyn is the fastest growing district in New Zealand in terms of both population and economic activity, and the district's roads are also becoming busier and experiencing more wear and tear."

Last year's residents' survey asked how the council should deal with a roading fund shortfall and 83 per cent of respondents supported spending more ratepayer money on roads instead of allowing them to decline.